I'm in no way expert on HDTV streams, but I admit that WOWOW versions are the best! I don't discard HDNet either - have not seen any others, could you post a comment with more info about OTA and sat HD channels?
I like D-Theater quality too... everyone today seems to be "codec masters" and says that MPEG2 has awful quality when used for HD, and H.264 is perfect. I agree that, at any (normal) given bitrate, H.264 is better than MPEG2, but when the latter has an enough high bitrate, it is capable to deliver very very good pictures, with not visible artifacts - or I'm simply watching my tv from too far, and I'm getting too old... (^^,)